N.B. The above advice, while accurate, carries some risk.
Using developer options to force apps onto the SD card (when the option to move them is unavailable) may cause some apps to misbehave (or even cease to function). Use it with caution, and it's better to go slowly; move just one or two apps at a time (avoiding anything of high importance), and test to see if things are working as expected.
Some apps just do not work on the SD card (notably including some of Google's own stuff…). The failure cases are generally not Nokia's fault, it's a generic Android / Google problem.
If you have inserted a new SD Card on and it is working fine on your Android Oreo 8.0 phone.Then follow the steps below:
1. Go to Smartphone “Settings“.
2. Scroll down and tap on the “Apps & Notifications“.
3. Now tap on the App info.
4. In the App Info, find the app from the list and tap on it to go insight the app options.
5. In the main “App info” screen tap on the “Storage” option.
6. Now Insight the Storage tap on “Change” or similar button which will appear below the Storage Used option.
7. A small on-screen selection dialog box will appear, from which select the “SD Card” radio button option.
8. And now the app will be moved to SD Card.